Direct Calibration of the Cepheid Period-Luminosity relation (Based on data from the ESA HIPPARCOS astrometry satellite)

P. Lanoix; G. Paturel; R. Garnier

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arXiv · astro-ph/9904298

Direct Calibration of the Cepheid Period-Luminosity relation (Based on data from the ESA HIPPARCOS astrometry satellite)

P. Lanoix·G. Paturel·R. Garnier

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Abstract

After the first release of HIPPARCOS data, Feast & Catchpole gave a new value to the zero-point of the visual Cepheid Period-Luminosity relation based on trigonometric parallaxes. Because of the large uncertainties on these parallaxes, the way in which individual measurements are weighted bears a crucial importance, and the discrepancy they show leads to the conclusion that the choice of the best weighting system can be provided through a Monte-Carlo simulation. On the basis of such a simulation it is shown that: - A cut in πor in σ_π / πintroduces a strong bias. - The zero-point is more stable when only the brightest Cepheids are used. - The Feast & Catchpole weighting gives the best zero-point and the lowest dispersion. After correction, the adopted visual Period-Luminosity relation is: = -2.77 log P - 1.44 \pm 0.05. Moreover, we extend this study to the photometric I-band (Cousins) and obtain: = -3.05 log P - 1.81 \pm 0.09.

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P. Lanoix, G. Paturel, R. Garnier. 1999-04-22. Direct Calibration of the Cepheid Period-Luminosity relation (Based on data from the ESA HIPPARCOS astrometry satellite). https://arxiv.org/abs/astro-ph/9904298

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